Adaptor for variable output photoflash apparatus

ABSTRACT

A variable output photoflash unit structured to be installed on and mechanically coupled to a particular line of commercial photographic cameras for automatic &#39;&#39;&#39;&#39;follow-focus&#39;&#39;&#39;&#39; control of its output, and an adaptor for adapting the photoflash unit for use with any camera having flash capability. The photoflash unit receives a multi-lamp photoflash assembly of the &#39;&#39;&#39;&#39;flash cube&#39;&#39;&#39;&#39; type and has adjustable attenuating means effective to attenuate a variable fraction of the luminous energy produced by the flash lamps in the assembly dependent upon the input received by a sensing probe. The adaptor accommodates the sensing probe and provides for manual selection of different levels of light output from the flash unit according to and in terms of the range of objects to be photographed.

United States Patent [1 1 Morse [111 3,745,323 [451 July 10,1973

[ ADAPTOR FOR VARIABLE OUTPUT PHOTOFLASH APPARATUS [75] Inventor:

[73] Assignee: Polaroid Corporation, Cambridge, I

Mass.

[22] Filed: May 6, 1971 [21] Appl. No 140,890

John B. Morse, Cambridge, Mass.

[52] US. Cl. 240/1.3, 95/11.5 R [51] Int. Cl. G031) 15/03 [58] Field ofSearch 24011.3:2 C;

[56] References Cited 7 UNITED STATES PATENTS 3,296,947 1} 1967Engelsmann et al 95/1 1.5 R X 3,369,467 2/1968 Land 240/1.3 X

3,390,621 7/1968 Land 240/13 X 3,491,667 l/1970 Land 95/11 R 3,517,1966/1970 Owens 240/].3 X

OTHER PUBLICATIONS Stump, G. P. Light Control for Electronic Flash UnitlBM Tech. Disclosure Bull. Vol. 8, No. 6, p. 876, Nov. 1965.

Primary ExaminerRichard C. Queisser Assistant Examiner-Joseph W. RoskosAttorney-Brown and Mikulka and Michael Bard 57 I ABSTRACT A variableoutput photoflash unit structured to be installed .on and mechanicallycoupled to a particular line of commercial photographic cameras forautomatic follow-focus control of its output, and an adaptor foradapting the. photoflash unit for use with any camera having flashcapability. The photoflash unit receives a multi-lamp photoflashassembly of the flash cube type and has adjustable attenuating meanseffective to attenuate a variable fraction of the luminous energyproduced by the flash lamps in the assembly dependent upon the inputreceived by a sensing probe. The adaptor accommodates the sensing probeand provides for manual selection of difi'er'ent levels of light outputfrom the flash unit according to and in terms of the range of objects tobe photographed.

18 Claims, 13 Drawing Figures Patented July 10, 1973 3,745,323

5 Sheets-Sheet 1 ATTORNEYS Patented July 10, 1973 5 Sheets-Sheet LPatented July 10, 1973 5 Sheets-Sheet FIG. 3

FIG. 4

IHUIi INVENTOR JOHN B. MORSE fl/zowzza/im, mm

Y B 3 O0 42 8 62 5 m 0 m0 0| 9 4 8 2 5 M# SHUTTER SPEED- 1/25 SEC.

ATTORNEYS Patented July 10, 1973 5 Sheets-Shcot FIG.5

INVENTOR JOHN B. MORSE BY fi/tozwz (Md W'iz and M AQKM ATTORNEYSPatented July 10, 1973 5 Sheets-Sheet H I/I/I/I/I/I/I/l/l/I I/ M LiINVENTOR JOHN B MORSE BY 10m MVMLZ FIG. 7

ATTORNEYS ADAPTOR FOR VARIABLE OUTPUT PHOTOFLASH APPARATUS BACKGROUND OFTHE INVENTION The difficulties encountered in attempting to produceproper flash illumination of photographed subjects at all objectdistances are well known. Stroboscopic flash units are offeredcommercially which are adjustable to vary the luminous output thereof.Such units are priced beyond the reach of a great many photographers,and even at their relatively high price are quite inconvenient, complex,and time-consuming in use. Typically, operating instructions for suchstroboscopic flash units require: 1) that the associated camera befocused; 2) that the correct aperture of the cameras objective beascertained for a given film sensitivity, fo-

cused distance, and shutter speed (normally by the use of a tableprovided); and 3) that upon obtaining the necessary information, theaperture of the camera objective be set accordingly. This procedure mustbe re-. peated each time a flash exposure is to be made at a differentfocused distance. The inconvenience of this procedure is manifest.

A low-cost variable output photoflash unit has recently been introducedby the assignee of this invention which is intended for use on certainof its commercial cameras. The flash unit is automatically adjusted inits light output to follow the focused distance of the associatedcamerathe greater the focused distance, the greater the luminous outputof the unit, up to a maximum level of light output determined by therating of the flash lamps employed. This flash unit is priced withinreach of the photographic mass market and is designed to use the popularflash cube multi-lamp flash assembly. However, because the flash unit isdesigned to be installed on and mechanically coupled to certain matingcameras exclusively for use in a followfocus mode of operation, thisflash unit has not, prior to this invention, been available to the verylarge numbers of photographers possessing non-compatible cameras.

OBJECTS OF THE INVENTION It is a general object of this invention toprovide manually adjustable variable output photoflash apparatus whichis capable of use with substantially all photographic cameras havingflash capability, and yet which is relatively inexpensive and extremelyconvenient to use.

It is another object of this invention to provide a lowcost, compact,and very simple adaptor for adapting for general use a commercial,low-cost variable output flash unit which is structured for coupledfollowfocus operation on certain commercial cameras only.

It is still another object that such adaptor make possible manuallyvariable flash illumination of objects at various ranges in accordancewith the focused distance of an associated camera, and that such manualfollowfocus operation is easy and convenient for the user.

It is another object to provide such an adaptor which simulates with lowcost and simple structure the nonlinear flash control characteristics ofthe said certain commercial cameras with which the flash unit isstructured for use.

It is still another object to provide improved methods of flashphotography.

Further objects and advantages of the invention will in part be obviousand will in part become apparent as the following description proceeds.The features of novelty which characterize the invention will be pointedout with particularity in the claims annexed to and forming a part ofthis specification.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of a photographiccamera having operatively mounted thereon variable output photoflashapparatus;

FIG. 2A is a fragmentary rear perspective of a photographic camerahaving a universal flash bracket;

FIG. 2B is a fragmentary perspective of a commercially availablevariable output photoflash unit;

FIG. 2C is a perspective of an adaptor according to this invention foradapting the FIG. 2B photoflash unit for general use with cameras suchas the camera shown in FIG. 2A and FIG. 1;

FIG. 2D is a bottom perspective of the adaptor shown in FIG. 2C as itmight appear if rotated from its FIG. 2C position;

FIG. 2E is a bottom perspective of the photoflash unit shown in FIG. 2Bas it might appear if rotated 90 from its FIG. 2B position;

FIG. 3 is a plan view, partly broken away, of the adaptor shown in theabove-described figures;

FIG. 4 is a side sectional view of the adaptor;

FIG. 5 is a front elevational view of the photoflash unit shown in theabove-described figures with front structure removedto show otherwisehidden components;

FIG. 6 is an exploded view of an array of apertured plates comprisingpart of the photoflash unit;

FIG. 7 is a fragmentary sectional view illustratinga trim assembly formaking fine adjustments in the luminous output of the photoflash unit;

FIG. '8 is a side sectional viewof the photoflash unit taken along lines88 in FIG. 7; and

FIG. 9 is a guide table for assisting in practicing a novel method offlash photography according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a commercial flashunit 144 mounted for use on a camera 146 (here shown as being of the35mm type) by means of a novel adaptor 148 representing one of the manypossible implementations of this invention. An understanding of thestructure and operation of the adaptor 148 will be expedited if thephotoflash unit 144 which is being adapted for general.

applicability is first described (see FIGS. 5 8).

The photoflash unit 144 is illustrated as including socket means, shownschematically at 150 (FIG. 7), for receiving a flash lamp assembly 152,known commercially as a flash cube." The assembly 152 contains fourindividual flash lamps, one of which is shown schematically at 154 andfour associated reflectors, one of which is shown schematically at 155.The flash lamps 154 are preferably of a commercially available highoutput type. Each of the lamps 154 is capable of pro ducing whenignited, a burst of luminous energy of predetermined high intensity andfixed duration. The photoflash unit 144 includes a stationary framemember 156 to which is affixed an attachment assembly 157. A

clear plastic cover assembly 158 is secured to the stationary framemember 156.

The photoflash unit 144 includes attenuating means for attenuating avariable fraction of the luminous output of an ignited lamp, comprisingan array 160 of apertured plates disposed within the cover assembly 158.The array 160 comprises four apertured plates 162, 164, 166, and 168disposed in overlying relationship (see FIGS. 5 and 6).

The apertured plate 162 is fixedly mounted within the cover assembly 158and is provided with a pair of oppositely directed ears 170 whichfunction to secure the plate 162 within the cover assembly 158. Theapertured plates 164, 166, and 168 are disposed successively rearwardlyof the fixed apertured plate 162 and are each slideable within the coverassembly 158 relative to one'another and to the fixed apertured plate162.

Each of the apertured plates 162, 164, 166, 168 defines a similar pairof spaced and generally rectangular apertures 172, 174. The pair ofapertures 172, 174 are so disposed as to establish in each plate a lowerportion 176, a central portion 178, and an upper portion 180. The lowerportion 176 of the plate 162 is provided with a generally rectangularopening 182 having an inwardly directed tab 184 extending from the upperlongitudinal edge thereof. Similarly, the plate 164 is provided with agenerally rectangular opening 186 having an inwardly directed tab 188extending from the upper longitudinal edge thereof.

The plate 166 includes a generally T-shape opening 190 in the lowerportion 176 thereof which is so configured as to define a pair ofinwardly extending shoulders 192. The T-shape opening 190 includes aninwardly directed tab 194 extending from the uppermost edge thereof.Similarly, the apertured plate 168is provided with a T-shape opening 196in the lower portion 176 thereof which is so configured as to define apair of inwardly extending shoulders 198. j

The longitudinal extent of the openings 182 and 186 and the distancebetween the inwardly extending shoulders 192 and 198 progressivelyincreases from the plate 162 to the plate 168. Also, the width (in thedirection of the longitudinal extent of the openings 182 and 186) of theinwardly directed tabs 184, 188, and 194, respectively, progressivelyincreases in correspondence to the increase in the width of the openings182, 186,

and the distance between the inwardly extending shoulder 192, 198. r i

In operation, upward movement of the plate 168 causes the tab 194 on theplate 166 to engage the shoulders 198 on plate 168 whereupon the plate166 is picked up and caused to move along with the plate 168. Continuedupward movement of the plates 166, 168 causes the tab 188 on the plate164 to engage the pair of shoulders 192 on plate 166 whereupon the plate164 is caused to move upwardly with the plate 166.

Further upward movement of the apertured plates 168, 166, and 164 bringsthe tab 184 on the plate 162 into engagement with the fixed lower edgeof the rectangular opening 186, precluding further upward movement ofthe plates 168, 166, and 164. In this position the array 160 of platesis in its position of least effective open area and thus of maximumattenuation.

Downward movement of the apertured plate 168 successively causes the tab194 to engage the uppermost edge of the T-shape opening 196, and the tab188 to engage the uppermost edge of the T-shape opening 190, whereby theplates 166 and 164 follow the downward movement of the apertured plate168 until such time as the tab 184 engages the uppermost edge of theopening 186 in the plate 164.

Actuating means are provided for adjusting the effective open area ofthe array 160 of plates and thus the light attenuation produced by theattenuating means. In the illustratedembodiment, the actuating meansincludes a lever arm 200 pivotally secured to the frame member 156 by apin 202. The lever arm 200 is biased counterclockwise (in FIG. 5) aboutthe pin 202 by a torsion spring 204. The lever arm 200 defines anarcuate slot 206 adapted to receive a guide pin 208 which is affixed tothe frame member 156 and which functions to guide the pivotal movementof the lever arm 200 about the pin 202.

A portion of the lower edge of the lever arm 200 is provided with a camsurface 210 and one end portion of the lever arm 200 is provided with apin member 212 which is rotatably and slideably received .within a slot214 in the rearmost apertured plate 168.

A link arm 216 is pivotally secured to the frame member 156 by a pin 218for pivotal movement in a plane normal to the plane of the array 160 ofapertured plates. The link arm 216 is biased for clockwise movement by atension spring 220, one end of which is secured to the frame member 156and the other end of which is secured to one end portion of the link arm216.

The link arm 216 has a generally cylindrical end portion 222 whichextends through a slot 224 in the front portion of the frame member 156.The slot 224 extends laterally across the front portion of thestationary frame member 156 whereby the cylindrical end portion 222 maytraverse said slot 224 in response to pivotal movement of said link arm216. The cylindrical end portion 222 of the link arm 216 is maintainedin engagement with the cam surface 210 of the lever arm 200 due to thebiasing of said lever arm 200 by said torsion spring 204 and the link216 by spring 220, as aforesaid.

A trim mechanism provides for fine adjustments in the light attenuationprogram of the attenuating means. The trim mechanism is shown asincluding a trim control link 226 pivotally secured by pin 218 to theframe member 156 beneath the link arm 216 and at the pivotal centerthereof. A driving link 228 is pivotally secured to the trim controllink 226 outwardly of the pin 218 by a pin 23.0. The link 228 functionsas a sensing probe for the photoflash unit 144, as explained in moredetail below.

The driving link 228 extends beneath the front 'portion of thephotoflash unit 144 to an end portion 232.

An end portion of the driving link 228 remote from said L-shape endportion 232 defines a bearing surface 236 which extends beneath andnormal to the plane of rotation of the driving link 228. An end portionof the link arm 216 remote from the cylindrical end portion 222terminates in a bearing surface 238 which depends therefrom generallynormal to the plane of rotation of the link arm 216. 7

An adjustment screw 240 is received in a threaded opening in the surface238 such that the portion of the adjustment screw 240 extendingoutwardly of the surface 238 may be varied as desired. The adjustmentscrew 240 serves to space the surface 236 a predetermined distance fromthe surface 238 such that movement of the driving link 228 apredetermined amount will cause the cylindrical end portion 222 of thelink arm 216 to move to a predetermined position dependent upon both theamount of movement of the driving link 228 and the setting of theadjustment screw 240.

The link arm 216 is caused to follow the driving link 228 because of thebias exerted on said link arm 216 by the tension spring 220. Also,movement of the trim control link 226 causes the driving link 228 topivot with the trim control link 226 about the pin 218 thereby movingthe bearing surface 236 away from the bearing surface 238. The tensionspring 220, however, causes the adjustment screw 240 to remain incontact with the surface 236 and the end portion 222 will be adjusted apredetermined amount by the movement of said trim control link 226, asaforesaid.

As suggested above, the driving link 228 acts as a mechanical sensingprobe for the photoflash unit 144. The mechanical input to link 228determines the state of the actuating means for the array 160 of platesperforming the variable attenuation function for the unit 144.

An input (a mechanical displacement) to the link 228 causes the link 228to pivot about pin 230, driving link arm 216 and, consequently, leverarm 200 to produce an adjustment in the relative positions of theapertured plates 162, 164, 166, and 168 and thus an adjustment in theeffective open area defined thereby. It is evident from the abovedescription that counterclockwise (in FIG. 8) displacement of link 228causes the array 160 of plates to move downwardly and open, increasingthe luminous output of the unit 144 when a flash lamp 154 is ignited.

Thus, as will be described more fully below, counterclockwise movementsof the link 228 are necessarily associated with flash illumination ofobjects at greater focused distances. Conversely, clockwise movements ofthe link 2 28, which result in larger fractions of the output of thelamps 154 being attenuated, are associated with flash illumination ofobjects at decreased range.

It should be understood that for any particular input to the link 228,the effective attenuation provided by the array 160 of apertured platesmay be selectively increased or decreased by adjustment of the trimcontrol link 226. For example, clockwise rotation of the trim controllink 226, as seen in FIG. 8, will cause the array 160 of plates to closeso as to decrease the efiective amount of light which will reach thesubject when a flash lamp is ignited.

One aspect of this invention is directed to the provision of an adaptor148 (FIGS. 1 4) which frees the photoflash unit 144 from its operationaldependency on a particular photographic camera or line of cameras, andenables the unit 144 to be used as a selfcontained, manually operable,variable output photoflash unit with any camera having flash capability.See especially FIGS. 2A 2B, 3, and 4.

For a more detailed description of the photoflash unit 144, referencemay be had to copending application, Ser. No. 101,336, filed Dec. 24,1970, and commonly assigned herewith to Polaroid Corporation.

The adaptor 148 is illustrated as comprising support means including ahousing 242, first mechanical interfacing means for connecting theadaptor 148 to a flash bracket 248 on a camera 146, and secondmechanical interfacing means for connecting the photoflash unit 144 tothe adaptor 148. The first mechanical interfacing means is shown ascomprising a foot 250 which is slideably received in and held by bracket(shoe) 248. The flash bracket 248 and foot 250 are shown as being of auniversal type in widespread use on hand-held photographic equipment.

The second mechanical interfacing means for connecting the unit 144 tothe adaptor 148 is illustrated as including a foot-like connector 252with flanges 254 and 256 which is received in the attachment assembly(shoe) 157. The connector 252 has formed on its inner periphery a ledgewhich supports a metal plate 258 having a centrally located slot 260 forpermitting entry into the adaptor 148 of the end 232 of link 228 on thephotoflash unit 144 when the unit 144 is connected to the adaptor 148.

A triangular-shape aperture 262 in the plate 258 is positioned toreceive a projection 264 on the end of a spring arm 266 comprising partof the attachment assembly 157 on the photoflash unit 144. Theprojection 264 snaps into the aperture 262 when the photoflash unit 144is operatively connected to the adaptor 148, signaling a properconnection of the photoflash unit 144 and precluding inadvertentdisengagement of the unit 144 from the adaptor 148.

The adaptor 148 includes novel manually adjustable means for driving thelink 228 on the photoflashunit 144 to vary the level of light outputfrom the photoflash unit 144 when a lamp 154 is ignited. The manuallyadjustable means includes an operator in the form of a wheel 270 andcouplingmeans for mechanically coupling the wheel 270 and the drivinglink 228 on the photoflash unit 144 such that the unit 144 is enabled toproduce a level of light output which is responsive to the setting ofthe wheel 270.

The wheel 270 is illustrated as having a stub axle 271 which is receivedfor rotation within a hollow cylindrical bearing 272. The wheel 270carries range indicia 276 indicating different levels of flash intensityin terms of distance to a scene object to be illuminated. The generalutility of the adaptor 148 and the usefulness of the range indicia 276will be described in more detail below in connection with a descriptionof an improved method of flash photography which maybe practiced usingthe teachings and structures of this invention.

The adaptor 148 includes indexing means for retaining the wheel 270 inpredetermined angular positions corresponding to pre-established levelsof luminous output of the unit 144. As revealed by the range indicia276, the indexing means acts to locate the wheel 270 in positions,hereinafter termed index positions, appropriate for flash exposures atfocused distances of, for example, 3.5, 4, '5, 7, and 10 feet.

The indexing means includes a plurality of angularly spaced recesses 274spaced on the periphery of the wheel 270 at locations corresponding tothe predetermined index positions of the wheel 270. Spring detent meanscomprising a leaf spring 278 retentively engages the recesses 274 in thewheel 270 one at a time to hold the wheel 270 in a selected one of itsindex positions.

The coupling means for coupling the operator wheel 270 to the drivinglink 228 includes a rotary-to-linear motion conversion mechanismresponsive to rotation of wheel 270 for driving link 228, comprising aslider 280 which is supported for linear reciprocatory movement in aslot 282 in a wall member 284 comprising part of the support means forthe adaptor 148. The

slider 280 has a nose 286 which engages the end 232 of the link 228 onthe photoflash unit 144 and is maintained in engagement therewith by thespring bias provided by spring 220, described above.

The rotary-to-linear motion conversion mechanism includes an axialprojection 288 on a face of the wheel 270 which engages and drives theslider 280. The projection 288 is located a predetermined radialdistance from the rotational axis of the wheel 270 and has a rounded end290 which engages the slider 280. FIG. 3 shows the wheel and slider setfor exposure of a scene object at close range, shown as 3.5 feet. Asecond position which the wheel 270 and slider 280 may assume when setfor exposure of an object near the far limit of the range for the flashunit 144 (e.g., 10 feet), is illustrated in broken lines in FIG. 3. Itcan be understood from FIG. 3 that as the wheel 270 is rotated, the end290 of the projection 288 traverses the contacted face 292 of the slider280 with a wiping action.

Referring to the actuating means for controlling the light attenuatingmeans (the array 160 of plates) in the photoflash unit 144 (see FIGS. 58)-it is important to understand that the displacement of the drivinglink 228 for a given change in effective luminous output from the unit144 is a highly non-linear function. More specifically, as the link 228is moved toward its far limit position (counterclockwise in FIG. 8),corresponding to maximum light output from the unit; e.g.,everdecreasing increments of displacement of the link 228 are requiredto produce equal changes in the effective luminous output of the unit144.

The rotary-to-linear 'motion conversion mechanism according to thisinvention produces a compensating non-linear displacement of the drivinglink 228. This is achieved by causing the wheel 270 to move through anangular locus of travel of predetermined extent and placement which issuch that, due to the action of the projection 288 on the slider 280,the linear displacement of the slider 280 is related to angulardisplacement of the wheel 270 by substantially a cosine function. Acosine function has been found to approximate satisfactorily thenon-linear displacement function of the link 228.-lt is manifest thatthis compensating rotary-to-linear motion conversion is providedaccording to this invention by a structure'which is extremelyinexpensive to manufacture and simple in construction and operation.

It should be understood at this point that the cam surface 210 of thelever arm 200 is of such shape, and the various components of thephotoflash unit 144 and adaptor 148 are so constructed and arranged thatthe net attenuation effected by the array 160 of plates in response toadjustment of the wheel 270 provides appropriate illumination for anobject to be photographed as a function of the range thereof.

As described in the introduction to this specification,

Using a photographic camera, as shown for example at 146, having aphotoflash unit 144 mounted for operation by the use of the noveladaptor 148, the user first sets an exposure value in the cameraappropriate for the sensitivity of the photosensitive materials beingused in the camera. A guide table such as is shown in FIG. 9 ispreferably provided to assist in the performance of this step. The usercan then make a series of flash exposures of objects at different rangesmerely by focusing the camera on the object to be photographed,ascertaining the range of the object focused on, and manually settingthe wheel 270 to correspond to the as certained range of the subject.The camera is then ready for triggering of the photoflash unit andcamera exposure apparatus to expose the photosensitive materials. Thus,by following the teachings of this invention, flash photography may bepracticed with consistent and predictable results and with very littleeffort and experience required. It has been found that the transfer offootage reading from the focus adjustment mechanism of a camera to thewheel 270 is made with extreme ease since the transfer is unencumberedby any requirement to make a conversion (or conversions) to anotherfactor or unit.

The invention is not limited to the particular details of constructionof the embodiments depicted, and it is contemplated that various andother modifications and applications will occur to those skilled in theart. For example, manually operable structures other than thoseillustrated for providing manual control of the effective output fromthe photoflash unit 144 are contemplated by this invention. The indiciaon the operator (or associated therewith) may represent different levelsof effective light output in terms other than object distances; however,for the reasons described above, the'indicia is preferably in terms offocused distances. The operator indexing means and mechanicalinterfacing structures are disclosed as but one of numerous possibleimplementations of the principles of this invention.

7 Therefore, because certain changes may be made in the above-describedapparatus without departing from the true spirit and scope of theinvention herein involved, it is intended that the subject matter of theabove depiction shall be interpreted as illustrative and notin alimiting sense.

What is claimed is:

1. An adaptor, for adapting a variable output photoflash unit havingmechanical sensing means for controlling said variable output, saidadaptor capable of use with a photographic camera having'a universalflash unit bracket, comprising:

support means including first and second mechanical interfacing meansfor connecting, respectively, said adaptor to a universal flash unitbracket on a camera and the photoflash unit to said adaptor;

a manually adjustable operator for selectively varying the level oflight output from the photoflash unit; and

coupling means for mechanically coupling said operator and the sensingmeans on the photoflash unit such that the photoflash unit is enabled toproduce a level of light output when energized which is responsive tothe setting of said operator.

2. The adaptor defined by claim 1, wherein said operator comprises amanually rotatable wheel and wherein said coupling means includes arotary-to-linear motion conversion mechanism responsive to rotation ofsaid wheel for driving the sensing means on the flash unit.

3. The adaptor defined by claim 2, including means to mount said wheelto rotate about an axis substantially orthogonal to a principaldirection of light propagation from the photoflash unit when connectedto said adaptor, and wherein said rotary-to-linear motion conversionmechanism includes a slider which is supported for linear reciprocatorymovement in engagement with the sensing means on the photoflash unit,said wheel having a projection which engages and drives said slider.

4. The adaptor defined by claim 3, wherein said projection acts on saidslider such that the linear displacement of said slider is related toangular displacement of said wheel by substantially a cosine function.

5. The adaptor defined by claim 2, wherein said wheel carries footageindicia indicating different levels of flash intensity in terms ofdistance to a scene object to be illuminated.

6. The adaptor defined by claim 2, wherein said wheel defines aplurality of radially spaced recesses denoting predetermined indexpositions of said wheel, and wherein said adaptor includes spring detentmeans for retentively engaging said recesses one at a time to hold saidwheel in a selected one of said index positions.

7. For use with a photographic camera, the combination comprising:

a manually adjustable variable output photoflash unit, comprising:

socket means for receiving a flash lamp assembly containing a pluralityof individual flash lamps and associated reflectors, each lamp beingcapable of producing, when ignited, a burst of luminous energy ofpredetermined fixed intensity and duration, and

adjustable attenuating means for attenuating a variable fraction of theluminous output of an ignited lamp comprising a plurality of aperturedplates mounted for relative translational movement so as to vary theeffective open area thereof, said attenuating means including actuatingmeans for effecting said relative movement of said apertured plates anda sensing probe for controlling said actuating mechanism; and

an adaptor for adapting said variable output photoflash unit for usewith a photographic camera having a universal flash unit bracket,comprising:

support means including first and second mechanical interfacing meansfor connecting, respectively, said adaptor to a universal flash unitbracket on a camera and said photoflash unit to said adaptor,

a manually adjustable operator for selectively varying the level oflight output from said photoflash unit, and

coupling means for mechanically coupling said operator and said sensingprobe on said photoflash unit such that said photoflash unit is enabledto produce a level of light output when energized which is responsive tothe setting of said operator.

8. The apparatus defined by claim 7, wherein said operator comprises amanually rotatable wheel and wherein said coupling means includes arotary-to-linear motion conversion mechanism responsive to rotation ofsaid wheel for driving the sensing probe on the flash unit.

9. The apparatus defined by claim 8 including means for mounting saidwheel to rotate about an axis substantially orthogonal to the principaldirection of light propagation from said photoflash unit, and whereinsaid rotary-to-linear motion conversion mechanism includes a sliderwhich is supported for linear reciprocatory movement in engagement withsaid probe, said wheel having a projection on one face thereof whichengages and drives said slider.

10. The apparatus defined by claim 9, wherein said projection acts onsaid slider such that the linear displacement of said slider is relatedto angular displacement of said wheel by substantially a cosinefunction.

11. The apparatus defined by claim 10, wherein said wheel carriesfootage indicia indicating different levels of flash intensity in termsof distance to a scene object to be illuminated.

12. The apparatus defined by claim 11, wherein said wheel defines aplurality of radially spaced recesses denoting predetermined indexpositions of said wheel, and wherein said apparatus includes springdetent means for retentively engaging said recesses one at a time tohold said wheel in a selected one of said index positions.

13. A device for varying theeffective light output from a flash lamphaving when ignited a luminous output of predetermined fixed durationand intensity, comprising:

support structure including flash housing means;-

socket means within said housingfor receiving a flash lamp includingmeans for applying energy to ignite the lamp;

adjustable attenuating means within said housing means for attenuating avariable fraction of the light produced by the lamp when ignited, saidattenuating means having a sensing probe which is movable to vary saidfraction of light attenuated; and

a manually rotatable operator carried by said support structure which iscoupled to said sensing probe of said attenuating means throughrotary-to-linear motion converting means for selectively varying thelevel of effective light output from the lamp.

14. The device defined by claim 13, wherein said operator carriesindicia representing different levels of effective light intensity interms of distance to a scene object to be illuminated.

15. The device defined by claim 13, wherein said operator comprises awheel and wherein said device includes means to mount said wheel torotate about an axis substantially orthogonal to a principal directionof light propagation from the device, and wherein said rotary-to-linearmotion converting means includes a slider which is mounted for linearreciprocatory movement and which engages said sensing probe, said wheelhaving a projection on one face thereof which drives said slider.

16. The device defined by claim 15, wherein said projection acts on saidslider such that the linear displacement of said slider is related toangular displacement of said wheel by substantially a cosine function.

17. The device defined by claim 16, wherein said wheel carries footageindicia indicating different levels of flash intensity in terms ofdistance to a scene object to be illuminated.

18. The device defined by claim 17, wherein said for retentivelyengaging said recesses one at a time to wheel defines a plurality ofradially spaced recesses dehold said wheel in a selected one of saidindex posinoting predetermined index positions of said wheel, tions. andwherein said device includes spring detent means

1. An adaptor, for adapting a variable output photoflash unit havingmechanical sensing means for controlling said variable output, saidadaptor capable of use with a photographic camera having a universalflash unit bracket, comprising: support means including first and secondmechanical interfacing means for connecting, respectively, said adaptorto a universal flash unit bracket on a camera and the photoflash unit tosaid adaptor; a manually adjustable operator for selectively varying theleVel of light output from the photoflash unit; and coupling means formechanically coupling said operator and the sensing means on thephotoflash unit such that the photoflash unit is enabled to produce alevel of light output when energized which is responsive to the settingof said operator.
 2. The adaptor defined by claim 1, wherein saidoperator comprises a manually rotatable wheel and wherein said couplingmeans includes a rotary-to-linear motion conversion mechanism responsiveto rotation of said wheel for driving the sensing means on the flashunit.
 3. The adaptor defined by claim 2, including means to mount saidwheel to rotate about an axis substantially orthogonal to a principaldirection of light propagation from the photoflash unit when connectedto said adaptor, and wherein said rotary-to-linear motion conversionmechanism includes a slider which is supported for linear reciprocatorymovement in engagement with the sensing means on the photoflash unit,said wheel having a projection which engages and drives said slider. 4.The adaptor defined by claim 3, wherein said projection acts on saidslider such that the linear displacement of said slider is related toangular displacement of said wheel by substantially a cosine function.5. The adaptor defined by claim 2, wherein said wheel carries footageindicia indicating different levels of flash intensity in terms ofdistance to a scene object to be illuminated.
 6. The adaptor defined byclaim 2, wherein said wheel defines a plurality of radially spacedrecesses denoting predetermined index positions of said wheel, andwherein said adaptor includes spring detent means for retentivelyengaging said recesses one at a time to hold said wheel in a selectedone of said index positions.
 7. For use with a photographic camera, thecombination comprising: a manually adjustable variable output photoflashunit, comprising: socket means for receiving a flash lamp assemblycontaining a plurality of individual flash lamps and associatedreflectors, each lamp being capable of producing, when ignited, a burstof luminous energy of predetermined fixed intensity and duration, andadjustable attenuating means for attenuating a variable fraction of theluminous output of an ignited lamp comprising a plurality of aperturedplates mounted for relative translational movement so as to vary theeffective open area thereof, said attenuating means including actuatingmeans for effecting said relative movement of said apertured plates anda sensing probe for controlling said actuating mechanism; and an adaptorfor adapting said variable output photoflash unit for use with aphotographic camera having a universal flash unit bracket, comprising:support means including first and second mechanical interfacing meansfor connecting, respectively, said adaptor to a universal flash unitbracket on a camera and said photoflash unit to said adaptor, a manuallyadjustable operator for selectively varying the level of light outputfrom said photoflash unit, and coupling means for mechanically couplingsaid operator and said sensing probe on said photoflash unit such thatsaid photoflash unit is enabled to produce a level of light output whenenergized which is responsive to the setting of said operator.
 8. Theapparatus defined by claim 7, wherein said operator comprises a manuallyrotatable wheel and wherein said coupling means includes arotary-to-linear motion conversion mechanism responsive to rotation ofsaid wheel for driving the sensing probe on the flash unit.
 9. Theapparatus defined by claim 8 including means for mounting said wheel torotate about an axis substantially orthogonal to the principal directionof light propagation from said photoflash unit, and wherein saidrotary-to-linear motion conversion mechanism includes a slider which issupported for linear reciprocatory movement in engagement with saidprobe, said wheel having a projection on one face thereof which engagesand drives said slider.
 10. The apparatus defined by claim 9, whereinsaid projection acts on said slider such that the linear displacement ofsaid slider is related to angular displacement of said wheel bysubstantially a cosine function.
 11. The apparatus defined by claim 10,wherein said wheel carries footage indicia indicating different levelsof flash intensity in terms of distance to a scene object to beilluminated.
 12. The apparatus defined by claim 11, wherein said wheeldefines a plurality of radially spaced recesses denoting predeterminedindex positions of said wheel, and wherein said apparatus includesspring detent means for retentively engaging said recesses one at a timeto hold said wheel in a selected one of said index positions.
 13. Adevice for varying the effective light output from a flash lamp havingwhen ignited a luminous output of predetermined fixed duration andintensity, comprising: support structure including flash housing means;socket means within said housing for receiving a flash lamp includingmeans for applying energy to ignite the lamp; adjustable attenuatingmeans within said housing means for attenuating a variable fraction ofthe light produced by the lamp when ignited, said attenuating meanshaving a sensing probe which is movable to vary said fraction of lightattenuated; and a manually rotatable operator carried by said supportstructure which is coupled to said sensing probe of said attenuatingmeans through rotary-to-linear motion converting means for selectivelyvarying the level of effective light output from the lamp.
 14. Thedevice defined by claim 13, wherein said operator carries indiciarepresenting different levels of effective light intensity in terms ofdistance to a scene object to be illuminated.
 15. The device defined byclaim 13, wherein said operator comprises a wheel and wherein saiddevice includes means to mount said wheel to rotate about an axissubstantially orthogonal to a principal direction of light propagationfrom the device, and wherein said rotary-to-linear motion convertingmeans includes a slider which is mounted for linear reciprocatorymovement and which engages said sensing probe, said wheel having aprojection on one face thereof which drives said slider.
 16. The devicedefined by claim 15, wherein said projection acts on said slider suchthat the linear displacement of said slider is related to angulardisplacement of said wheel by substantially a cosine function.
 17. Thedevice defined by claim 16, wherein said wheel carries footage indiciaindicating different levels of flash intensity in terms of distance to ascene object to be illuminated.
 18. The device defined by claim 17,wherein said wheel defines a plurality of radially spaced recessesdenoting predetermined index positions of said wheel, and wherein saiddevice includes spring detent means for retentively engaging saidrecesses one at a time to hold said wheel in a selected one of saidindex positions.